Screw.



E. C. HOLMES.

SCREW.

APPLICATION FILED JUNE 20. 1914.

Patented D60. 24, 1918.

SCREW.

neeasea.

Specification of Letters Patent.

Patented Dec. 2a, was;

Application filed June 20. 1914. Serial No. 846,231.

To all whom it may conccrm.

Be it known that I, EDWARD (J, HOLMES, a citizen of the United States,and a resident of the city of Norwood, Hamilton county, Ohio, haveinvented certain new and useful Improvements in Screws, of Which thefollowing is a full, clear, and exact description, reference being hadto the accompanying drawings, forming a part of this specification. 7 I

It is now a conceded fact, based upon long usage, that the common orordinary railway spike is inadequate and not in harmony with the factorof safety that is and should be demanded in laying and keeping in placethe rails of modern times. known that a screw forced into timber hasmany times the holding power over any form of like nature that could bedriven into wood, even if the latter form were designed with barbs anddepressions. The

purpose of the screw which forms the subject of this invention is toprovide a screw spike which will force itself into all kinds of hardwood easily and quickly, with the least amount of labor. In order toaccomplish this purpose I combine in my screw the functions of thedrill, tap and screw,

' and that it may be more eficient it-is provided with two flutes one oneither side, .so

as to facilitate cutting power and? prevent as much as possible therising to the surface t, is also well of chips and sawdust. Instead ofthe fiber being broken as is the case with the spike driven into thewood, the fiber of the wood is cut and threaded, each thread forming astrong factor of resistance. The head of the spike is formed so that asocket piece will fit over it, and this socket is preferably for use asa special brace, said brace being used exclusively for screwingthe spikein and out of the railway. tie. All of which will appear more clearly inthe following specification, and the novelty of which will be dulyclaimed.

In the drawing, The figure is a side elevation of the screw. The head 1of the screw spike is of the special shape shown in the drawing, so asto accommodate a special shaped chuck, and has a beveled under surfaceso as to engage the flange of a rail when used in railroad constructionwork. 7

The shank 3 of the screw is cylindrical in shape, and of considerablelength. This shank is of one diameter only, because if the shank taperedat all, the task of turning so heavy a spike into a thick, hard timbersuch as a railroad tie, would be impracticable altogether. It is on thisshank that the screwthreads are formed, preferably six standard threadsto the inch, and running clear to the head, or not, as desired.

At the end of the shank is the taper 5. This taper is preferably made byflattening the edges of the screwthreads so as to cause the shank toslope ofl at a taper to a blunt point.

The screw end is to all intents and purposes that of a standard drill ofthe gage of the screw, the taper being cut to form the cutting edges 7,7, and the clearance spaces flutes 6, 6, may be made straight, but forthe reasons to be developed the spiral is preferred. In the first place,the providing of a screw with a head, a strai ht, that is, cy-'lindrical shank, a taper, a H11, and clear- I ance spaces of any kindprovides a screw slpike which will go into the wood and stay t ere.Other spikes will go in, but will not stay, being in the form of agimlet. Others have no clearance spaces, or else have a tapered shank,and W111 not gointo the hard.

woods under practical conditions without first havin a hole bored forthem.

While either straight or spiral flutes can be employed, ll have foundthat for hard woods such as oak or hickory, the spiral flutes arepreferable over the straight.

When the spike is inserted in, say a railroad tie, it is set in placewith no hammering, and simply screwed in. The taper passes in easilybeing part of a drill, and the shank of the screw being cylindrical andof uniform diameter, there 1s no wedging apart, the planes of thethreadscarrying the screw in easily. The presence of the flute is necessary totake care of the wood displaced by the screw in going in. If thisremoved wood or chip becomes wedged in the flutes, then only greatpressure would sufice to send in the screw. The drill portioncontinually cuts out away for itself and sends upwardly this spiral formto efi'ectually prevent jamming of the drill chips.

The advantage of a screw over a straight spike, is clear without anyremark. The necessity of boring a hole is done away with by my s ike, byhaving a drill end, and the final di culty of clogging and unduefriction is overcome by so providing for the ,chips drilled out as thescrew sinks that they messes wood without a preliminary boring thereof,15

-- comprising a dull portion at the one end thereof, comprising aplurality of cuttin edges, a head portlon, a cylindrical shank portionhaving contiguous screw threads cut thereon, a taper portion between theshank and the drill, and a plurality of spiral flutes, one for eachcuttin edge, extending up the shank and terminatlng below the head,substantially as described.

' EDWARD C. HOLMES. Witnesses:

HELEN L. AICHHOLZ, ANNA- F. DIENST.

